Oscillating burster cone assembly for boring type miner head



B. F. TRACY v OSCILLATING BURSTE R CONE ASSEMBLY FOR BORING TYPE MINER HEAD Filed Sept. 29, 1954 2 Sheets-Sheet 1 "illllll IN V EN TOR.

y Benjamin Tracy 7 4 M* ATTORNEY Feb. 26, 1957 TRACY 2,783,038

OSCILLATING BURSTER CONE ASSEMBLY FOR BORING TYPE MINER HEAD Filed Sept. 29, 1954 v 2 Sheets-Sheet 2 mun- MINI"- INVENTOR.

Ben amm F Tracy BY A 7 TORNEV OSCILLATlNG BURSTER CONE ASSEMBLY FOR EQRING TYPE MINER HEAD Benjamin F. Tracy, Point Pleasant, W. Va., assignor to Goodman Manufacturing Company, Chicago, 11]., a

This invention relates to improvements in burster cones for use on boring heads of mining machines.

Mining machines of the boring head type are commonly provided with a burster cone projecting axially at the front end of each boring head, with a pilot bit projecting from the front end of the cone. Such cones and bits usually are fixed to and rotate with the boring head, and have a coarse spiral thread along its tapered surface. Since the cone is of relatively small diameter, however, it rotates slowly, with the result'that it is usually of limited effectiveness for its intended purpose of bursting out or dislodging the core of mineral left adjacent the center of the bore made by the boring head.

Among the objects of the present invention is to provide an improved form and arrangement of burster cone which is non-rotatable when inserted in the working face, so as to increase the bursting and material-dislodging effect of the cone.

A further object of the invention is to provide a rotatable pilot bit in advance of the non-rotatable burster cone, so as to combine the advantages of initial penetration of the standing face with the greater bursting and dislodging effects of a non-rotating cone.

Other objects of the invention will appear from time to time as the following description proceeds.

The invention may best be understood by reference to the accompanying drawings, in which:

Figure 1 is a view in side elevation of a boring head for a mining machine constructed in accordance with my invention, and showing the boring head in boring position in a mine face.

Figure 2 is a detail front view of the burster cone and pilot bit shOWn in Figure 1, with the ends of the radial arms of the boring head omitted.

Figure 3 is an enlarged section taken on line 3-3 of Figure 2.

Figure 4 is a view in side elevation of a boring head having a modified form of burster cone, which is designed for laterally oscillating movement relative to the working face.

Figure 5 is a detail front view of the form of cone and pilot bit shown in Figure 4, and

Figure 6 is an enlarged section taken on line 6-6 of Figure 5.

Referring now to details of the embodiment of the invention shown in Figures 1, 2 and 3, this embodiment illustrates a relatively simple form, in which the burster cone is non-rotatable, and non-oscillable. A boring head of conventional type is indicated generally at 10, its main elements consisting of a hub 11 and a pair of radially extending arms 12, 12, on each of which is mounted two forwardly projecting cutter supports 13, 14, with bit clusters 15, 16 at their forward extremities for cutting circular kerfs A and B, respectively, in the Working face of a mine.

At the front end of hub 11 is concentrically mounted a burster cone assembly, consisting of a base plate 20, a forwardly projecting stub shaft 21 and a burster cone tats atent ice 22 rotatably mounted on said shaft. The base plate 20 may be fixed as byscrews 20a to the hub. The shaft 21 has a reduced rear end portion 23, keyed at 24 in the base plate 20 and an intermediate portion 25 of slightly larger diameter about which thecone 22 is' rotatable, as by a bearing bushing 26 keyed at 27. The shaft 21 is fixed to the base plate by suitable means, herein consisting of a nut 28 on the threaded inner end of the reduced portion 23, arranged to hold the shouldered rear end 29 of the intermediate shaft portion 25 in engagement with the front face of the base plate 20.

The stub shaft 21 projects forwardly through bearing 26 and cone 22, to form an exposed shank 30 of a pilot bit assembly, hereinconsisting of a cutter bit 31 secured at the front end of said shank, and a coarse helical thread 32 surrounding said shank.

The burster cone 22 is provided with a plurality of radially disposed fins 35, herein four in number, extending longitudinally of its tapered outer face, designed to enter the working face to restrain said cone against rotation in the working face while the core is exerting a bursting or wedging action upon the standing core left within the circular kerf B. However, the pilot bit assembly consisting of the bit 31 and vane 32 on shank 30 will continue to be rotated with the cutter head to penetrate the center of the core and make way for entrance of the burster cone 22 as the boring head is advanced into the working face.

Suitable annular grease and dust seals 36 and 36a for the rotatable bearing surfaces of the cone 22 are seated, respectively, between the rear end of the cone and the bearing 26, and the front end of the cone and a shoulder 37 at the rear end of the shank 30.

In the modified form of the invention shown in Figures 4, 5 and 6, the burster cone assembly has a base plate 40 fixed as by screws 40a to the hub 11, with a stub shaft 41 having its rear end keyed at 42 in the base plate. Said shaft has an integral shank 43 at its front end, having a helical thread 44 and terminal pilot bit 45 thereon similar to the thread and pilot bit of the form previously described. A hollow burster cone 46 is mounted for relative rotation and oscillation on the shaft 41 between the base plate 40 and the shank 43.

The front end of said cone has a cup-shaped bearing socket 48 at its front end engaging a semiball shaped bearing 49 on a correspondingly shaped enlargement 50 at the tapered base 51 of shank 43, to afford relative oscillation and rotation of said burster cone about the center of the bearing 49. An annular grease and dust seal 52 may be recessed about the bearing face of the bearing socket 48.

Oscillation of the cone is controlled by an eccentric 53 keyed at 54 on the shaft 41, and having a semi-ball shaped bearing ring 55 fixed thereon. The bearing ring 55 is engaged by a twopart bearing ring 56 suitably mounted within the hollow rear end of the cone. The rear face 57 of the cone surrounding its hollow rear end is preferably convex in shape, struck on the center of the semi-ball shaped bearing 49 at the front end of said cone, and said rear face has fitting engagement against a concave face 58 formed in a bearing plate 59 fixed to the front end of the base plate 40 as by screws 59a. An annular grease and dirt seal 60 may be mounted near the outer rim of the bearing plate 59, to close the hollow rear end of the cone in all positions of oscillation of said cone.

The oscillating cone 46 is provided, as before, with a plurality (here four) of radially disposed fins 62 extending longitudinally of its tapered outer face to restrain said cone against rotation in the working face'while it is exerting a bursting or wedging action upon the standing core left by the boring head 10. The bursting efiect Patented Feb. 26,1957

3 of; the cone is: enhanced by its oscillating movement as indicated in the dottedand full-line positions indicated in Figure 4.

Although I have shown and described certain embodiments of my invention, I do not wish to be understood as limiting myself to.the-exact construction shown and described but that various changes. and modifications may be made without. departing from the spirit and scope.

of the invention as defined in the appended claims.

I claim:

1. A boring head having a hub and cutter device thereon to cut an annular kerf in a mine face, a shaft projecting forwardly axially of said hub having a pilot cutter atits front end, and aburster member rotatably mounted on said shaft between said hub and said pilot cutter, the rotatablev mounting; of, said burster member comprising a ball-like-bearingtinember at its front end and an eccentric bearing between the rear end of said burster member and said shaft, to permit oscillation of the rear end of said burster member as the shaft rotates.

2. The structure of claim 1, wherein the burster mem- Cir 4 her has a plurality of longitudinally projecting fins along its outer surface to restrain rotation of said burster member relative to the working face.

3. The structure of claim 1, wherein the body of the burster member is of hollow conical shape, with its smaller end at the front thereof, and with the eccentric bearing means enclosed in the enlarged rear end thereof.

4. The structure of claim 3, wherein the rear end of the burster member has a convex bearing surface engaging a concave bearing surface on the hub to close the rear of said burster member in all positions of oscillation thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,603,621 McKinlay Oct. 19, 1926 2,720,391 McCarthy et a1. Oct. 11, 1955 FOREIGN PATENTS 692,542 Great Britain June 10, 1953 

